TAMODEX 20 MG TABLET is used in the treatment and prevention of breast cancer. TAMODEX 20 MG TABLET is an a hormone-based medication. It works by binding to oestrogen receptors and blocks the effects of oestrogen (a natural female hormone) in the breast tissue. This slows down the growth and multiplication of breast cancer cells. In addition, it also treats female infertility due to a failure to produce and release eggs (ovulate) properly.